Mobile apps have a distinctive problem. Most are currently standalone programs, that often just converse with an app server run by the company that wrote the app. The apps do not have URL links within them.
It is much harder for a search engine, which is optimised to search the Web for webpages, to search arbitrary apps. There is no standard syntax equivalent to an URL or URI to enable this.
To enable such and other functionality in mobile apps has been termed ‘deep linking’ within apps. (The term also has an earlier use that refers to standard web pages and URL links within them. This submission does not use that earlier meaning.)
Major companies have several projects aimed at defining deep links. Facebook Corp. has App Links. Google Corp. has App Indexing. Twitter Corp. has App Cards. There are also several startups, like Branch Metrics Corp., Quixy Corp. and URX Corp., with their own initiatives. The syntax and functionality vary between these company-specific efforts.
Bitcoin has implemented a blockchain. The latter is a distributed electronic ledger of transactions. There is recent work by others to generalise the use of blockchains. One example is Ascribe Gmbh, a German startup company, which uses the Bitcoin blockchain to store the provenance (ownership history) of (mostly at this time) digital assets. It has produced SPOOL—Secure Public Online Ownership Ledger protocol and implemented this in a product. Directed at the art market for digital artworks.